Odour from septic tank

adocholiday

Hi all,

I have a standard concrete pit in the ground type of septic tank. We're in the house 3 years. The tank was pumped just before we moved in and we had it pumped back in April. Since it was last done we've noticed a strong gassy odour in the garden at times and I suspect it is from the tank, it can be very strong at times. I've tried securing the metal lid over the pit cover but it hasn't made much difference.

Any suggestions for what the cause and solution might be?

the_pen_turner

why did you empty it.

where are the vents

it there a vent on the main stack at the house

are you using domestos etc in your toilets

are your sinks, washing machine etc going into it aswell

adocholiday

Emptied it because it was near full. Not what you mean about the main stack at the house? The tank is about 20 metres from the house and the toilets, shower, sinks and washing machine all go into it. We use bleach to clean the toilets yeah.

I've added a sketch of the setup here: https://i.imgur.com/Yy4ogeE

the_pen_turner

https://www.boards.ie/discussion/comment/118203778#Comment_118203778

a septic tank will always be full unless its leaking. if there is a high level of solids then there is an issue . its probably the bleach or the washing machine killing the backteria in the tank. when the pipe comes out of the house there should be a pipe that goes up the wall and over the gutter level to vent out any smells and to alow in air so the system isnt pulling a vacuum .

where does that pvc pipe from the tank go. can you re route it and vent it farther away

Don't be using bleach or strong detergents in the toilets or down the sink. They kill the natural bacteria which keep the tank operating. If you upset the bacteria balance you'll get a smell.

Under normal circumstances the tank fills, the bacteria take care of the solids, and the liquid is piped into a nearby soakhole which would have been dug at the time the tank was built. Washing machines, showers, and dishwashers don't normally drain into the septic tank as they dilute the bacteria and upset the normal balance of human waste that goes into it. They should be draining into the soakhole as well, or into other drains specifically for waste household water.

That's how it was when we built our house.... regulations may be different now.

Our septic tank is in situ for nearly 50 years and we only needed to have it emptied once, I can't remember now why we had to do that.

adocholiday

There's no pipe going over any of the gutters. Might this be the issue? Where the pipe comes out of the house there is a plastic cover over the pipe in the ground and that's it. Definitely no pipe going up from the ground.

The pipe coming out of the side of the tank doesn't go anywhere as such, it just ends at the wall. I could try extending that, wouldn't be an issue I have lots of space.

the_pen_turner

https://www.boards.ie/discussion/comment/118203901#Comment_118203901

those 2 vent pipes are there to move the smells up and away from where you can smell them. not having them is definetly part of your issue. even more so if your sealing the metal lid, the incomeing water has to drive out something and that will be the smelly air around the lid or where ever it can.

i would bet that you also get smells in the house

the bleech is a major issue and should be stopped straigth away.

adocholiday

Definitely no vent pipes around the house, 1 sewer pipe comes out the back of the house that carries waste to the septic tank. No odours in the house at all thankfully, just in the garden.

The 2 pvc pipes in the tank vent gas into the chamber above that's covered by the metal lid. The metal lid does not seal around the chamber, it just sits over it so gas could be escaping from under it. And the pipe to the outside of the chamber just ends at the wall it doesn't go anywhere.

I'm going to extend that pipe down the garden to take the gasses further away as a first step and I'll replace the bleach with septic tank friendly cleaners. Not sure what I can do with the metal lid other than try to seal it with something, will have to look into it.

Thanks for the advice.

Up Donegal

To qoute in the hat - "Washing machines, showers, and dishwashers don't normally drain into the septic tank as they dilute the bacteria and upset the normal balance of human waste that goes into it. They should be draining into the soakhole as well, or into other drains specifically for waste household water."

Doesn't ALL the waste water from the house have to go to the septic tank nowadays as a planning condition?

https://www.boards.ie/discussion/comment/118228743#Comment_118228743

You could be right...I'm not up to speed on the latest regulations. When we built 45 years ago you had to deal with waste household water/ run-off from gutters etc separately to the septic tank. Now with the big percolation area and modern tanks it could be different.

adocholiday

Yeah we're actually building an extension at the moment and the contractor had to reroute the kitchen waste pipes which were all connected to the septic system. Only the gutters now go to a separate run off.

In some modern designs the vent pipe comes up through the roof, rather than outside.

adocholiday

We definitely have no vent pipe for the septic anywhere at the house but there's no odour in or around the house, it's only in the vicinity of the septic tank itself

obriendj

Hi adocholiday

I came across your post and we have the exact same issue

3 years after moving in we emptied the tank.

The smell is around the tank but like yourself not in the house.

Did you have any luck with resolving.

Thanks

Obriendj

Wearb

Say roughly where you're located. There are usually local lads that specialise in ground works that are good at fixing such issues.

obriendj

https://www.boards.ie/discussion/comment/118930997#Comment_118930997

Thanks in Dublin South West if you know anyone who specializes

adocholiday

Hi there,

Unfortunately I haven't resolved it but just because we've been working on a renovation and extension so it's not top of the list. I did stop using bleach when cleaning though and that does seem to have made a difference but it's still there at times. It was less important throughout the winter because we're not spending time in the garden but I'll be making a big effort to resolve it in the coming weeks.